A series of reactions in which a signal is passed on to downstream proteins within the cell via PKR, an intracellular protein kinase that is activated by stress signals or upon binding to double-stranded RNA (dsRNA), followed by autophosphorylation. PKR plays a role in the antiviral response, phosphorylating proteins such as the translation initiation factor eIF2 to inhibit protein synthesis during viral infection. Begins with activation of PKR activity, and ends with regulation of a downstream cellular process, e.g. regulation of transcription or inhibition of translation.